It has been well known that fatty acids with a relatively high purity are substantially free of smell, but they will generate their characteristic unfavorable smell of deteriorated/rancidity smell when irradiated with ultraviolet ray, allowed to stand under atmospheric conditions for a relatively long period of time, or treated by heating. As a method to improve such unfavorable smell, there has been employed from old a method for cooking foods, for example, fatty acid-containing products such as fishery products and meets, with spices such as a capsicum, pepper, wasabi, Japanese pepper, garlic, and ginger. Such a method, however, is not a method for reducing the formation of ingredients of deteriorated/rancidity smell per se, but one for imparting a strong stimulant flavor and taste to the ingredients to mask the unfavorable smell, and as a demerit it may often change preferable flavor and taste, and even color tint inherent to products containing fatty acids. Accordingly, improvement of such a conventional method has been required. In addition to the above fatty acid-containing products, there has been known that, as in the case of rice, denaturation of fatty acids in rice is easily occurred, i.e., rice will promptly reduce in freshness just after milling and may easily generate a smell of rice bran, a kind of deteriorated/rancidity smell. Since the level of such a smell of rice bran is even said to be an index of freshness of rice or a criterion for quality retention, the establishment of a method for inhibiting the smell of rice bran has been strongly desired.
Recently, it has been employed a method for improving smell to inhibit the dispersion of ingredients of deteriorated/rancidity smell, which uses the inclusion action of cyclodextrins. The method, however, has been known to have the defect that the ingredients of deteriorated/rancidity smell, which had been once included by the cyclodextrins, may be replaced with other substances susceptible to the inclusion action and then release the captured unfavorable smell; and that the effect of improving smell is not sufficient.
In view of these conventional defects in conventional prior arts, the present inventors energetically studied the influence of saccharides, i.e., mono- and di-saccharides, on the formation of volatile aldehydes from fatty acids and/or the decomposition of fatty acids, based on a completely novel technical idea of inhibiting the formation of ingredients of deteriorated/rancidity smell, particularly, volatile aldehydes per se and/or the decomposition of fatty acids per se, without improving the formed deteriorated/rancidity smell. As a result, as disclosed in Japanese Patent Kokai No. 2001-123,194, the present inventors had found that α,α-trehalose and/or maltitol significantly inhibit the formation of volatile aldehydes from fatty acids, as well as the decomposition of such fatty acids, and then they provided a method for inhibiting the formation of deteriorated/rancidity smell and compositions, wherein the formation of volatile aldehydes and the decomposition of fatty acids are inhibited by the above method; and they established a novel agent for inhibiting the formation of volatile aldehydes and/or the decomposition of fatty acids and use thereof.
These disaccharides, i.e., α,α-trehalose and maltitol, however, have a lower sweetening power than that of sucrose but have a relatively strong sweetness due to disaccharides. Therefore, when applied to compositions rich in fatty acids, relatively large amounts of α,α-trehalose and maltitol are needed to sufficiently inhibit the formation of volatile aldehydes and/or the decomposition of fatty acids, and this will inevitably over sweeten the resulting compositions and may deteriorate their inherent properties such as taste. Since α,α-trehalose and maltitol are quite easily crystallizable saccharides, they may be crystallized when handled at a relatively high concentration. It was also found that, as the defect, the inhibitory action of the formation of volatile aldehydes and the decomposition of fatty acids as mentioned above will not be expected when α,α-trehalose and maltitol are crystallized.
From these reasons, there has been desired the establishment of oligosaccharides which can inhibit the formation of volatile aldehydes from fatty acids and/or the decomposition of fatty acids and which have a relatively high molecule, lower sweetening power, and non-crystallinity. While, the applicant of the present invention had disclosed in Japanese Patent Kokai No. 143,876/95 that saccharide derivatives of α,α-trehalose are prepared from reducing partial starch hydrolyzates and that the saccharide derivatives can be used in food products, cosmetics, and pharmaceuticals. However, the above-identified Japanese Patent Kokai Nos. 2001-123,194 and 143,876/95 never disclose anything about whether the saccharide derivatives of α,α-trehalose inhibit the formation of volatile aldehydes and/or the decomposition of fatty acids similarly as in α,α-trehalose and/or maltitol.